Hulls of the ships and their methods of construction

ABSTRACT

A hull of a ship comprises a plurality of longitudinally spaced transverse frames on which are mounted in succession, a first continuous skin, a plurality of spaced longitudinal ribs and a second continuous skin. The skins and ribs are assembled on the frames with the latter in inverted position, and the assembly is inverted when completed.

United States Patent Bruniaux et al.

HULLS OF THE SHIPS AND THEIR METHODS OF CONSTRUCTION Bernard Jean Pierre Louis Lucien Bruniaux, Chatenay Malabry; Roger Jean Le Corre, Courrevoie, both of France Etat Francais-Delegatlon Ministerielle Pour L'Armement, Paris, France Filed! June 25, 1970 Appl. No.: 49,865

Inventors:

Assignee:

Foreign Application Priority Data June 25, 1969 France ..6921218 US. Cl. ..1 14/65 R Int. C B631) 3/00 Field of Search ..l 14/78-85, 72-74,

114/74 R, 74 A, 74 T, 76, 69, 65 R, 65 A; 9/6, 1 R l T, 1 A, 2 R; 244/117 R, 119,120,125, 126, 129 R; 220/10, 15, 9 LG 1 June 20, 1972 [56} References Cited UNITED STATES PATENTS 2,743,465 5/1956 Vogel ..9/6 3,339,778 9/1967 Herrenschmidt 220/10 X 3,538,878 10/1970 Zalman ..114/68 2,310,765 2/1943 Domier 244/1 17 R 2,816,298 12/1957 Foster ..9/6 3 ,093 ,847 6/1963 Strecker .9/ 6 2,397,049 3/ 1946 Sandison 1 14/82 X 3,007,208 11/1961 Urban ..9/6 X 2,384,966 9/1945 Rowland 1 14/84 X 1,885,198 11/1932 Hale ..1 14/82 Primary Examiner-Milton Buchler Assistant Examiner-F. K. Yee Attorney-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT A hull of a ship comprises a plurality of longitudinally spaced transverse frames on which are mounted in succession, a first continuous skin, a plurality of spaced longitudinal ribs and a second continuous skin. The skins and ribs are assembled on the frames with the latter in inverted position, and the assembly is inverted when completed.

9 Claims, 2 Drawing Figures HULLS OF THE SHIPS AND THEIR METHODS OF CONSTRUCTION BRIEF SUMMARY OF THE INVENTION This invention relates to ships hulls and particularly to watertight hull assemblies formed of transverse bulkheads, longitudinal ribs and a continuous hull skin or plating.

More particularly the invention relates to hulls whose length lies between 20 and 60 meters and whose beam is between 5 and meters and which comprises at least ribs below the waterline. Vessels comprising such hulls may in particular be mine sweepers.

The invention is also such hulls.

An object of the invention is to make such hulls better able to meet the various practical requirements, particularly with respect to longitudinal resistance, sound insulation and elimination of the presence of the ribs from the interior space in the hull. The invention contemplates the assembly of hulls of the type indicated above by successive superposition from the inside to the outside of transverse frames, a first continuous skin or plating, longitudinal ribs and a second continuous skin or plating, these various elements being preferably made of timber.

In the preferred embodiments, resort is made to one or more of the following arrangements:

Each of the two skins is constituted in a known manner by superposition of a first wall formed of juxtaposed, longitudinal elements transversely spliced together and at least two other thinner walls of mutually crossing diagonals;

The enclosed spaces bounded transversely by the skins and ribs is divided lengthwise into compartments, preferably by bulkheads arranged transversely in relation to the frames, and the compartments are filled with a cellular substance;

The thickness of each skin remains the same throughout its extent and the crosswise spacing between successive ribs is substantially the same between all these ribs, such spacing being practically the same as the width of one rib at the bot tom of the hull, whereas the height of each rib, i.e. its crossdirected to methods of construction of wise dimension perpendicular to the adjacent surfaces of the skins becomes greater the nearer such rib approaches the waterline;

The ribs are mounted on the outer face of the first skin by means of a first countersunk assembly passing through these ribs from the outside with their heads countersunk in the ribs, and the second plating is mounted on the ribs by means of a second countersunk assembly from the outside and being out of contact from the first assembly, the difierent elements of the assemblies being preferably spikes, screws or bolts of stainless steel.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic transverse section through a portion of a hull according to the invention, and

FIG. 2 shows, on a larger scale, a segment of such portion of the hull.

DETAILED DESCRIPTION By way of general introduction, the hulls of ships of comparatively large dimensions, i.e. length greater than 20 meters and a width greater than 5 meters are generally constituted of:

a series of channel-section transverse frames, arranged parallel to each other in longitudinally spaced relation;

a number of longitudinal ribs running the entire length of the hull and assembled with, the frames on the inside thereof so as to brace them;

and a plating or continuous the frames.

Such hulls introduce a certain number of disadvantages, among which are the following:

Their longitudinal strength is not sufficient to withstand the severest conditions to which the hull is subjected;

They do not form a good acoustic screen between the inside and outside of the hull;

hull skin externally mounted on The existence of the ribs on the inside of the frames renders considerable spaces located lengthwise between such frames as practically unusable or at least considerably complicates the inside arrangement.

This invention corrects these drawbacks by mounting the ribs on the outside of the skin itself fastened in the usual manner on the outside of the frames and then covering the assembly with a second skin or outer plating.

In the drawings, the frames are denoted by by 2, the ribs by 3 and the external skin by 4.

To complete the excellent stiffness of the "frame girder" thus constituted, rigid bulkheads 5 are preferably added transversely with respect to the frames in various lengthwise positions each transversely bounded by the two skins 2 and 4 and by two consecutive ribs.

These bulkheads 5 divide the passageways between the skins and ribs into separate compartments which are filled with cellular material 6 such as a foam rubber.

Each of the skins 2 and 4 is preferably constructed in the manner described in French Pat. No. 1,355,791 filed Feb. 8, 1963 and issued Feb. 10, 1964.

These skins each comprises:

a first wall composed of juxtaposed, lengthwise elements (21, 41) each engaged with the next by insertion of round tou gues (22, 42) whose radius is slightly less than half the thickness of the element, in a corresponding groove comprising an arch slightly less than the arc of the tongue, so that two neighboring elements may, by intersplicing, assume an angular inclination with respect to the hull section;

and a second wall composed of at least two layers of diagonals (23, 43) of planking or other material, the orientation of the elements corresponding to the successive layers being intercrossed.

In the embodiment illustrated, the first skin comprises two layers of diagonals carried externally on the spliced element wall 21 and the second skin comprises four layers of diagonals of which two are carried internally and two externally on the wall of elements 4.

Further, the outermost layer of the second skin is lined with a protective cover 7 composed preferably of a resin reinforced with glass fiber.

The various elements constituting the hull are preferably made of a material such as timber or reinforced plastic material which is magnetically and electrically insulative.

In a preferred embodiment given by way of nonrestrictive example, the frames and ribs are made of plywood.

In the preferred embodiment, the spaces between successive ribs remain identical all around the hull, as does the thickness of each skin: to obtain increased sound insulation and strength at the lower parts of the hull, all that is necessary is to vary the transverse sections of the ribs.

These transverse sections are usually rectangular and the width of each rib is preferably of the same order of magnitude as the space between two consective ribs at the lowest portions of the hull. In these latter zones, the height of each rib is of the order of twice its width, while the rib section is substantially square at the level of the waterline.

The building of such a hull is preferably carried out in inverted condition: first the frames are placed with their concavity facing downward, then the frames are covered with first skin 2 in known manner, for example by means of screws or spikes 8 for wall 21 and coupling pins for walls 23; then onto the skin 2 are mounted the ribs 3 and bulkheads 5, preferably by means of screws 9 and nut-and-bolt units 10 countersunk into these ribs with their heads flush; the cavities thus formed are lined with foam material 6', and finally the second skin is mounted on the outside of the cavities thus lined, preferably by means of screws or spikes 1 I and coupling pins; the various assembly methods described above are supplemented by adhesively joining the elements together. It then suffices to line the assembly with the protective coating 7 and invert the finished hull.

If it is desired to avoid the creation of electric or sound wave leak paths between the inside and the outside of the hull, it will 1, the first skin be advantageous to obviate any contact between the various metallic assembly elements 8, 9, l0, and 11 and even to make these of a non-magnetic material such as stainless steel.

The hull thus constructed offers numerous advantages over those hitherto existing, and in particular, as follows:

It exhibits exceptional longitudinal strength because of i frame girder construction which allows, in particular, increase of the longitudinal spacing of the frames, which can run for example from 0.5 to 0.9 meters for a ship 55 meters long;

The increase of its strength toward the bilges is effectively and simply guaranteed without any increase in the thickness of its platings or in the distribution density of its ribs;

It forms an effective soundwave barrier;

it enables the inside space of the vessel between the frames; to be fully utilized.

its buoyancy is increased, as also its safety against damage because it comprises two distinctly separate skins and an ample cushion" compartment between these two skins.

As is self-evident and follows moreover from the foregoing, the invention is not limited to its methods of utilization or to the methods of constructing its various parts, but on the contrary it covers all variants thereof as defined in the appended claims.

What is claimed is:

l. A ship hull comprising a plurality of longitudinally spaced transverse frames; a first continuous skin means positioned externally of said frames and enclosing the same, a plurality of longitudinally extending spaced ribs extending along the external surface of said first skin means, fastener means extending through said first skin means for securing said ribs to said frames, a second continuous skin means positioned externally of said ribs and enclosing same in spaced relationship to said first skin means to form an outer covering for the hull, a plurality of generally transversely extending longitudinally spaced bulkheads interposed between adjacent ones of said ribs and between said first and second skins so as to divide each of the spaces therebetween into compartments, and cellular material filling said compartments.

2. A hull according to claim 1, wherein each of the two skin means comprises a first wall of longitudinal, juxtaposed elements transversely spliced one to the next, and at least two other thinner walls of intercrossed diagonals.

3. A hull according to claim 1, wherein each skin means has a thickness remaining the same throughout its extent, the transverse spacing measured normal to the surfaces between the successive ribs being substantially the same between all said ribs, said spacing being substantially equal to the width of one rib at the bottom of the hull, the height of each rib as measured in its transverse dimension perpendicular to the adjacent surfaces of the skin means becoming proportionately smaller as the ribs approach the waterline.

4. A hull according to claim 1, comprising first assembly elements mounting said ribs on said first skin means on the outer surface thereof, said assembly elements extending through said ribs from the outside thereof and having heads which lie flush in said ribs and second assembly elements mounting said second skin means on said ribs, said second assembly elements extending from the outside of the second skin means and being out of contact with the first assembly elements.

5. A hull according to claim 4, wherein said assembly elements are constituted of material which is magnetically insula tive.

6. A hull according to claim 5, wherein said assembly elements are fasteners of stainless steel.

7. A hull according to claim 1, wherein said ribs and skin means are constituted by timber elements.

8. A method of assembling the hull of a ship, comprising the steps of; positioning a plurality of transversely extending frames in a longitudinally spaced array, mounting a first continuous skin assembly externally on said frames, positioning a plurality of longitudinally extending transversely spaced ribs on the outer surface of said first skin assembly, fastening said ribs to said frames, positioning a plurality of generally transversely extending longitudinally spaced bulkheads between adjacent ones of said ribs so as to form closed spaces, filling said closed spaces with a cellular insulating material, and mounting a second continuous skin assembly on the outer surfaces of said ribs in spaced relationship to said first skin assembly so as to form a hull having a plurality of insulated compartments.

9. A method according to claim 8 wherein said frames are initially supported in inverted position so as to be concave downward, and the skins, frames, and ribs are inverted after being assembled together. 

1. A ship hull comprising a plurality of longitudinally spaced transverse frames; a first continuous skin means positioned externally of said frames and enclosing the same, a plurality of longitudinally extending spaced ribs extending along the external surface of said first skin means, fastener means extending through said first skin means for securing said ribs to said frames, a second continuous skin means positioned externally of said ribs and enclosing same in spaced relationship to said first skin means to form an outer covering for the hull, a plurality of generally transversely extending longitudinally spaced bulkheads interposed between adjacent ones of said ribs and between said first and second skins so as to divide each of the spaces therebetween into compartments, and cellular material filling said compartments.
 2. A hull according to claim 1, wherein each of the two skin means comprises a first wall of longitudinal, juxtaposed elements transversely spliced one to the next, and at least two other thinner walls of intercrossed diagonals.
 3. A hull according to claim 1, wherein each skin means has a thickness remaining the same throughout its extent, the transverse spacing measured normal to the surfaces between the successive ribs being substantially the same between all said ribs, said spacing being substantially equal to the width of one rib at the bottom of the hull, the height of each rib as measured in its trAnsverse dimension perpendicular to the adjacent surfaces of the skin means becoming proportionately smaller as the ribs approach the waterline.
 4. A hull according to claim 1, comprising first assembly elements mounting said ribs on said first skin means on the outer surface thereof, said assembly elements extending through said ribs from the outside thereof and having heads which lie flush in said ribs and second assembly elements mounting said second skin means on said ribs, said second assembly elements extending from the outside of the second skin means and being out of contact with the first assembly elements.
 5. A hull according to claim 4, wherein said assembly elements are constituted of material which is magnetically insulative.
 6. A hull according to claim 5, wherein said assembly elements are fasteners of stainless steel.
 7. A hull according to claim 1, wherein said ribs and skin means are constituted by timber elements.
 8. A method of assembling the hull of a ship, comprising the steps of; positioning a plurality of transversely extending frames in a longitudinally spaced array, mounting a first continuous skin assembly externally on said frames, positioning a plurality of longitudinally extending transversely spaced ribs on the outer surface of said first skin assembly, fastening said ribs to said frames, positioning a plurality of generally transversely extending longitudinally spaced bulkheads between adjacent ones of said ribs so as to form closed spaces, filling said closed spaces with a cellular insulating material, and mounting a second continuous skin assembly on the outer surfaces of said ribs in spaced relationship to said first skin assembly so as to form a hull having a plurality of insulated compartments.
 9. A method according to claim 8 wherein said frames are initially supported in inverted position so as to be concave downwards, and the skins, frames, and ribs are inverted after being assembled together. 